Daylight,
There are a lot of narrow gauge passenger cars in the Golden State. Many of the museums have them. The N-C-O Historical Society is the newest group that is collecting narrow gauge cars. They have a coach and a combine as well as freight car bodies.
The reason for so much narrow gauge is the SP's Owens Valley Line which ran until 1960. The SP moved the cars from several narrow gauges like the South pacific Coast and others down to the Owens Valley.
Another group that has cars from there is the Society for the Preservation of Carter Brothers Railroad Resources at Fremont, California. There is a good roster on their web site.
Ted Miles, SPCBRR Life Member